DE 195 02 574 A1 discloses a detector having two or more parallel detector rows, which run in the direction of the axis of an object, for example a patient, through which X-rays are to be passed. Two or more detector rows may be configured as a mounting unit, for example as a detector module. In this case, a sensor array formed from a large number of sensor elements is mounted on a printed circuit board. The sensor elements have slightly different characteristics. The characteristics of the sensor elements are also dependent on the temperature. In consequence, image artifacts may occur.
U.S. Pat. No. 5,799,057 discloses a detector in which the frame can be heated by means of a heating device. The frame normally has a non-standard temperature emission. It is impossible to ensure that the temperature is constant over all the sensor elements.
A further possible way to avoid image artifacts is to calibrate each sensor element. This can be done by using a special measurement device to produce calibration tables. The calibration tables contain, for example, information about the temperature response, about the radiation drift response, about the relative signal strength, about the persistence response, about the position dependency of the signal strength, about the beam response or defective sensor elements.
In order to produce calibration tables such as these, the detector modules have to be heated to predetermined temperatures by way of a special heating apparatus, and the corresponding calibration data then has to be determined. It is possible, for example, to use an electrical heating cover as the heating apparatus, which is fitted to the rear face of the detector modules. The fitting of a heating cover such as this is time-consuming since the electrical connections between the detector modules and the downstream evaluation electronics must be disconnected first of all. A further problem is that the heating cover does not rest uniformly on all the detector modules. In consequence, the detector modules are not heated to the same temperature.